The invention relates to a waste storage device and a method of operation of such a device.
One known waste storage device is disclosed in GB Patent No. 2206094 (incorporated herein by reference) and described here with reference to FIG. 1. The device is particularly useful for the storage for subsequent disposal of waste such as babies"" nappies or other personal waste material. A plastics container 21 is formed with an internal flange 22 from which a cylinder 23 extends upwards. A pack consisting of a tubular core 1 inside a profusely circumferentially pleated length of flexible tubing 2 is located in the container 21 with the core 1 resting on the flange 22 and rotatable on the cylinder 23. To begin using the pack to form a series of packages of objects, which in this particular example will be considered to be babies"" disposable nappies, the top of the flexible tubing 2 is pulled upwards and tied into a knot 24. This closed end can then form the bottom of a package to be formed along the length of part of the tubing. This is effected by pushing the closed end downwards inside the core 1 and cylinder 23 by the object to be packaged. As this is being done the flexible tubing 2 from the pleated length slides over the top edge 25 (FIG. 1) of the core 1 which is made sufficiently smooth to prevent the flexible tubing from being damaged. The core 1 may be approximately four inches (10.16 cm) diameter but, of course, the diameter of the flexible tubing 2 is substantially more Man this.
When the object has been thrust well into the concentric core 1 and cylinder 23, the package is closed by twisting the flexible tubing 2 above the object as at 30 (FIG. 1). This is done by turning the core 1 with remaining pleated tubing thereon about the core axis. A unit 31 is formed for this purpose in that it has a depending annular flange 50 formed with an outer surface that is a taper fit in a frusto-conical inner surface 51 at the top of the core 1. The package is prevented from turning about the axis of the core during this manual twisting action by springs 52 fixed to the container 21 and projecting radially inwards to engage the package. These springs are equidistantly spaced round the container 21. Shallow, grooves dividing upwardly extending ridges are formed on the frusto-conical inner surface 51 to stop slippage of the flexible tubing during the twisting operating.
By the aforesaid means, a series of connected closed packages 35 are formed and this can be continued until the pleated tubing 2 is exhausted. In the arrangement of FIG. 1 the packages collect in a bin portion 36 of the container closed at the bottom by a hinged base 53 normally held closed by a manually operable catch of suitable type. When it is desired to remove the packages from the bin portion 36 for transport to a waste disposal facility, the uppermost package is severed above its upper twisted closure 30 and the hinged base 53 opened for the removal of the packages through the end of the bin portion. Even if the twisted seals between the packages become loosened, the lid and the newly formed topmost twisted seal with prevent the escape of odours, vapours and gases to the ambient atmosphere. However, it has been found that when the tubing 2 is made of high density polyethylene the twisted joints remain remarkably tight.
A development of this arrangement is disclosed in GB 2292725 (incorporated herein by reference) and described here with reference to FIG. 2. It will be seen that an outwardly flared funnel 12 having an inlet edge 15 is detachably connected to the top of the core 1 by a taper joint 16. The funnel improves the hygiene of the device yet further because the flexib drawn from the pack as an object is pushed down, over the inlet edge 15 of the funnel 12 to present a fresh and hygienic layer of tubing in the flared part of the funnel. The funnel 12 is twisted to obtain the twisted closure 30. An alternative spring arrangement 14 is shown in FIG. 2 and described fully in GB 2292725. GB 2206094 and GB2292725 both additionally disclose a cutting arrangement for severing the tubing when it is desired to remove the packages for disposal. A farther improved cutting arrangement is described in International Patent Application No. GB99/00243 which is incorporated by reference herein.
These known systems allow a simple and hygienic method of storing a large number of sanitary objects or packages such as diapers for disposal in an odour-free environment. However a certain amount of manual intervention is required for example opening lid, pushing the package through the Jaws and twisting the tubing above it. In particular in some commercial applications the user may wish to perform the operation with minimum intervention in particular to minimise contact with an apparatus containing waste from different origins.
The invention is set out in the claims. The invention provides a simple, low intervention, hygienic pedal operated system. The invention can be used without the need for twisting in one embodiment, a pair of rollers pinching a storage bag to prevent escape of odours, and the rollers may be symmetrically driven to rotate, improving the operation of the system. Alternatively a pair of paddle rollers allow the waste to be drawn down between successive pinch points. Provision of sensors allows the operation to be automated.
References herein to a storage bag or bag relate also to the flexible tubing discussed above having a knotted or otherwise closed end, or in its open configuration but acting as a bag.